This work was supported in part by the NSF (DMR-0804088) and startup funds from Washington University in St. Louis. Y.X. was also partially supported by the World Class University (WCU) program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology (R32-20031). Part of the research was performed at the Nano Research Facility, a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation under award ECS-0335765.

Keywords:

electrocatalysis;

high-index facets;

nanostructures;

oxygen reduction reaction;

platinum

Many facets: A simple synthetic route, which is based on reduction in aqueous solution, results in Pt concave nanocubes (see picture) enclosed by high-index facets such as {510}, {720}, and {830}. The nanocrystals exhibit electrocatalytic activity (per unit surface area) that is 3.5 times higher than the commercial Pt/C catalyst in the oxygen reduction reaction.